Used the U.V. oil dye. Head gasket oil leak!! need help

First off would like to say the UV oil dye works VERY well. I drove down the street and back and sure enough with the blacklight over the engine bay the oil is seeping out of the passenger side middle section at the head gasket. Probably the last place I was hoping it would be from. I am fairly new to the XJ world. How tough of a job is it to replace the head gasket? am I better off just buying a newer XJ?

Thanks,
JT

Here's a link to a head removal on a 4.2L motor.
http://www.off-road.com/jeep/new/40conv.html
It's different than the 4.0 but close enough to outline what you need to do, and ithas good pictures. Take a look at that and if you think you're capable of it go for it. I've taken the head off of a motor, I had never done it before, it's a bit daunting, but it's not too terribly difficult. Just make sure you hae the proper tools needed, torque wrench and such.

JTS97Z28 said:

I drove down the street and back and sure enough with the blacklight over the engine bay the oil is seeping out of the passenger side middle section at the head gasket.

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Any chance you might be referring to the valve cover gasket?

JTS97Z28 said:

Probably the last place I was hoping it would be from.

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If it is the valve cover gasket it's an hour job, TOPS.

JTS97Z28 said:

I am fairly new to the XJ world. How tough of a job is it to replace the head gasket?

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Very easy job if it's the valve cover gasket, it's held on by like 14 bolts, there are several write-ups on doing it.

JTS97Z28 said:

Am I better off just buying a newer XJ?

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Not if it's just the valve cover gasket, no.

I'll pulled the head off my 94 4.0l twice now. I've got a Borla exhaust, and that makes things a bunch easier.

It's heavy head. It's a lot easier to bolt down the manifolds with the head out, but it's a lot harder to manhandle the head around. If you've got a helper, that may be the way to go.

A couple of alignment dowels will keep the gasket in place while you gently put the head down. Be careful to not tear the gasket.

You will want to have the head checked for flatness and cracks while it's off.

Before we get too far into this...

Did you clean the engine BEFORE you added the dye, and only run it for a bit? A valve cover leak can present as a head gasket - but the dye should help to narrow down the location.

The head is not difficult to remove and re-install, but do take a moment to check the heads of the studs for paint marks - if you see any, GET NEW HEAD BOLTS! If you aren't sure, get new bolts. If you reuse the bolt, PAINT THEM (colour doesn't matter, but it should be fairly bright and obvious.) The 242 head bolts can only be reused ONCE - they're likely to fail if you torque them down a third time.

Also, make sure you have some Teflon paste or LocTite PST (Pipe Thread Sealer) - you'll want to use it on the driver's side front bolt, since it goes into the water jacket. Installing that bolt dry is a great way to get a coolant leak.

I've found it helpful to unbolt the manifold collector (two bolts,) then unbolt the head, and remove the head and manifolds all at once. Service the manifold gasket on the bench, and install as a unit - if you are able. You'll probably want help, or want to be fairly large (the assembled head and manfolds mass about 60-80#, and being two feet long doesn't help.) If you get help, make DAMN SURE they can follow instructions IMMEDIATELY and AS GIVEN - you're ultimately responsible for any repairs to your vehicle, which means you must be in control of things...

Get a 9/16" universal socket (short socket with inbuilt universal joint) for servicing the manifold bolts - it will help, even on the bench.

I believe the head bolts are 16m/m (threaded 1/2-13 - maybe 11/16" then) and you can get a "mid" length socket from Sears for that driver's side rear bolt. Either that, or unbolt the transmission and jack up the tailshaft, which will give you some clearance at the firewall.

It's not a difficult job, technically speaking, but you should keep your head screwed on good and straight, and have a manual handy. Clean the mating surfaces with either Scotch-Brite or a brass brush - anything more aggressive can cause trouble. I might use some very mild sandpaper - 400 grit or 600 grit ON A BLOCK - but the Scotch-Brite is just about best. Likewise on the manifold sealing surfaces - and you can use the "spent" SB on the valve cover - head and cover.

Any other questions? When you do this enough, you stop thinking about it, and you miss things when you start explaining them instead...

5-90

Ok to clarify a few things here. YES its the headgasket I know the difference between valve cover and the block/head. I have replaced my valve cover gasket several months ago.

And the leak is FOR SURE at the head gasket as the dye is coming from the center portion not leaking down at all from up top.

I cleaned the engine BEFORE I added the UV dye.

I am 100% certain where the leak is just getting an idea on how hard it is to pull the head and replace that gasket.

Thanks,
JT

No problem - I just wanted to make sure. I'm not trying to be insulting - I just want to make sure we're all on the same page before anyone gets too far into this...

The head is fairly simple - I find it easier than V-block engines - but it can be cumbersome to swing around - which is why I gave the advice I did. I've done it lone-handed the way I describe, but I'm a pretty big guy, and I'm used to moving around heavy things...

If you are reasonably sure you can handle something like that with your own muscle power, go for it - but if you are not at all sure, GET HELP.

Again, I'm really not trying to be insulting - I just wanted to make sure we're all on the same page, and I'm trying to give a little advice based upon my own experience...

5-90

JT:

I still think its your valve cover or its blowing up from your oil filter heck id beleive that before id beleive it was the head gasket... But you know you want that 01 Limited XJ so clean it up and sale it off... Oh by the way theres one more thing ... THE HEAD WEIGHS A TON...

bring it down here to dc and we can do it like MW98GTs ford i still have his spark plugs

Before I forget - all the oil that runs down the pax side of the cylinder head is drainback - the strongest force acting upon it is gravity. That's the side with the lifters and pushrods - those parts pump oil up to the top of the cylinder head, and then it drains back through the open galleries on that side.

Since there's no pressure on that side of the head gasket (there is pump pressure in the pushrods - but minimal pressure in the pushrods - like 2-5 pounds, tops,) I'd be inclined to check again. Since the oil drains down the "inside" of the open gallery there, there's not a lot of reason why you'd develop and oil leak there (it's just unlikely - not impossible.)

Other possible oil leaks - which are more likely...
Oil Filter Adapter - that's subject to full pressure at all times, and is only sealed with O-rings.
Valve cover gasket - these really do fail commonly. I've modified the FSM installation procedure, and it seems to work rather better for me that way.
Distributor base. Since the distributor drives the oil pump, it's possible that there's a slight shaft leak on the oil pump, which will spray the distributor shaft. This could manifest as a leak at the distributor base, and it could spray a little. There's usually a paper gasket on the flange at the base of the distributor.

Just offering advice. Honestly, if it was my rig, I'd be rechecking that leak - since I'd have some difficulty believing that it could leak there without some sort of assistance...

5-90

JTS97Z28 said:

And the leak is FOR SURE at the head gasket as the dye is coming from the center portion not leaking down at all from up top.

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If the leak is definitely from the head gasket but it's only very small, I'd be inclined to leave it alone and just observe in case it gets worse.
As 5-90 said, the pushrod oil galleries are on the passenger side of the head and there's no positive oil pressure in the galleries themselves (oil drains back into the block under gravity), so a small oil leak is nothing to fret about.

The other way to try first might be to clean and degrease that area with a good spray cleaner, brakekleen, etc. Once you have it good and degreased see if you can force some rtv in there. With it being a return area for the oil it would be more like a weep than a leak. Sometimes that rtv is enough, this is a tough time of year to do this unless you have a heated garage so you might want to consider it. Just a thought.

Yeah its not that big of a deal just an oil leak more of a annoyance that anything. I will actually try getting a picture Charles to show you where its coming from. I know for a fact its the head gasket.

Maybe there is even something I can do as a temporary fix or to slow down the oil leak such as a bead of sealant along the block/head gap.

Thanks again and I will try and see if a picture will come out under a blacklight when I get off work tonight. Its actually really cool.

JTS97Z28 said:

Yeah its not that big of a deal just an oil leak more of a annoyance that anything. I will actually try getting a picture Charles to show you where its coming from. I know for a fact its the head gasket.

Maybe there is even something I can do as a temporary fix or to slow down the oil leak such as a bead of sealant along the block/head gap.

Thanks again and I will try and see if a picture will come out under a blacklight when I get off work tonight. Its actually really cool.

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Make sure your CCV and PCV are working right. Those should draw enough negitive pressure to pull air in a small leak like that.
Also make sure the oil is draining back and not just laying up on top.

langer1 said:

Make sure your CCV and PCV are working right. Those should draw enough negitive pressure to pull air in a small leak like that.
Also make sure the oil is draining back and not just laying up on top.

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Well the thing is my CCV does not seem to be working correctly as I did have a decent amount of oil in my air filter housing. I also checked the hose that comes out of the rear section of the valve cover and it is not blocked. Right now I am running with the air filter passage blocked and am currently waiting for the new CCV valve to come in at Jeep as I broke it on accident. So right now that is just left open to vent. Either way the oiil leak has been there since the day i bought the Jeep which was almost a year ago so it cant be related to that.

Is there anything else I can check to make sure my CCV system works correctly? Also, I thought the 4.0 does not have a PCV?

Thanks again,
JT

Is there anything else I can check to make sure my CCV system works correctly? Also, I thought the 4.0 does not have a PCV?

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My 87 does. If yours is 91 or newer then it uses CCV.

You can try pulling the CCV lines, and blowing them out with carburettor cleaner. Once you've done that, take the time to clean out the baffles in the valve cover where the lines are hooked up, and clean the baffle in the airbox just for good measure.

It's usually buildup in the baffles that gets this whole thing started - cleaning that up will usually either eliminate or significantly reduce the problem. Something that should be given a seeing-to every few years. Since it's a CCV system, there is no valve to act as a "block" for the oil, and to be changed periodically.

5-90

JT

I dont know if you remember me putting the new style valve cover on my xj back at riddle but i had the ccv problem... I would do as 5-90 says.. Your xj does not have a PCV valve, but even with the new style valve cover i still get mild blowby... its part of an XJ.... YOu know you just want that 2001 limited with the heated seats (drooling) but i am sticking with my renix box that i love so dearley

Viva Renix
Viva La France

Ok just got back from in the garage and here is the deal. There is infact a very slight leak from the headgasket passenger side, BUT this does not seem like the main one. After more searching around with the blacklight it appears that the main leak is from the rear of the motor as I found a LOT of oil leaking from above the oil drain plug. Infact I havent even drivin the Jeep today and there was a puddle under it. So considering this where does it sound like my main culprit is now? rear main or the oil pan?

Thanks,
JT

look some more because a valve cover leak at the rear can drip down and look like a rear main seal leak. if it's leaving puddles i don't see how it is that hard to find the leak. clean the engine WELL with degreser and brush. and look for leaks use that black light stuff i ya like.

I did use degreaser I got everything very clean and even put in the UV dye. I see no evidence of the oil coming from the rear of the valve cover. I replaced the valve cover gasket when I bought the Jeep about 8 months ago.

Yes its leaving puddles but the reason its still hard to find is because the back of the motor is tough to see. All I know now is that the leak is coming from somewhere above the oil drain plug.